Electromagnetic Oscillations and Alternating Current Chapter 31 Electromagnetic Oscillations and Alternating Current In this chapter we will cover the following topics: -Electromagnetic oscillations in an LC circuit -Alternating current (AC) circuits with capacitors -Resonance in RCL circuits -Power in AC circuits -Transformers, AC power transmission (31-1)

L C (31-2)

L C (31-3)

L C (31-4)

1 2 3 4 5 6 7 8 (31-5)

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L C (31-9)

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O (31-13)

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O (31-15)

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SUMMARY Circuit Element Average Power Reactance Phase of Current Voltage Amplitude Resistor R Current is in phase with the voltage Capacitor C Current leads voltage by a quarter of a period Inductor L Current lags behind voltage by a quarter of a period (31-17)

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O A B (31-19)

O A B (31-20)

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(31-24) Transmission lines Erms =735 kV , I rms = 500 A Home Power Station Transmission lines Erms =735 kV , I rms = 500 A Home 110 V T1 T2 Step-up transformer Step-down transformer R = 220Ω (31-24)

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